<html>
    <head>
        <script type="text/javascript">
            function save(){
                var a1=document.getElementById('a1');
                document.getel
                var account=document.getElementById('a1').value;
                alert(account);
                a1.value="789";
                
            }
            </script>
    </head>
    
    <body>
        账号:<input id="a1" type="text">
        <br/>
        密码:<input id="a2" type="text">
        <br/>
        <input type="button" value="提交" onclick="save()">
    </body>
</html>